The invention relates to a frame for a centrifugal fan, and in particular to a frame for a centrifugal fan preventing impurities from entering the interior thereof and reducing reflow of air in a system.
Referring to FIG. 1, a conventional centrifugal fan comprises a frame 10, a motor (not shown), and an impeller 30. The frame 10 comprises an air inlet 11 and an air outlet (not shown). The motor is disposed in the frame 10, for activating the impeller 30 which comprises a hub 31, a base plate 32, and a plurality of blades 33 formed on the base plate 32. Air enters the centrifugal fan via the air inlet 11 and flows with the rotation of the impeller 30 and exits from the air outlet.
Referring to FIG. 2A and FIG. 2B, the conventional centrifugal fan is applied in a system 40 in which electronic members (not shown) are disposed. An air inlet 41 is formed on one side of a housing of the system 40. As shown in FIG. 2B, heat in the system 40 is dissipated by the centrifugal fan. Outside air enters the centrifugal fan via the air inlet 41 of the system 40. Air output from the air outlet of the centrifugal fan is forwarded to the interior of the system 40. The aforementioned operation of heat dissipation, however, has a drawback. An airflow output from the air outlet of the centrifugal fan causes reflow of air, reducing heat dissipation from the system 40.
To reduce the reflow of air, another system, as shown in FIG. 3, comprises a guide plate 42 disposed in a housing of the system and tightly abutting the centrifugal fan to reduce the reflow of air.
Specifically, as shown in FIG. 3, the guide plate 42 abuts the centrifugal fan by a surface thereof contacting a turning corner on an outer frame of the centrifugal fan. Accordingly, the guide plate 42 contacts the centrifugal fan merely in a linear manner. Thus, reflow of air is also easily generated when linear contact between the guide plate 42 and the centrifugal fan is incomplete.
Moreover, as the air inlet 41 of the system 40 is connected to the exterior thereof, impurities, such as dust and water drops, may enter the system 40 via the air inlet 41. The impurities may also enter the centrifugal fan, causing damage thereto.
Hence, there is a need for a frame of a centrifugal fan to reduce reflow of air in a system and enhance heat dissipation thereof. In addition, external impurities can be reduced in the centrifugal fan such that damage thereto is prevented.